"I am not sure about your grounding idea either. "

I think if you check your house wiring, you will find it is grounded this
way, if you have a house built within the last 30 years or so at least.

"You forgot zoned heat piping and an underground tunnel so he never has to
go
outside. LOL"

ditto

Most likely the existing wire will be used for lighting circuit and a new
line run. For those talking about how "cheap wire is" have you priced 10-3
w/ground direct burial wire lately? It will take a season or two to
re-establish a nice lawn over the trench also.

Now for the "black tape, etc" comment, do you run two black wires to/from
your wall switches? Since you break the black, this is what you should do,
right? Better check to see all of yours are that way.

I wasn't very clear, the thought was to come from a new 220V breaker. The
problem is the neutral would not have individual insulation, but would be
insulated within the bundle, which in the case of the neutral, shouldn't
make that much difference.

Thanks,

Walt Conner